1. Field of the Invention
The invention relates to a filter, especially for filtration of electromagnetic interference, with a base element, with at least one electrical filter component and with at least two input terminal contacts and at least two output terminal contacts for connection of the conductors of an electric line, the input terminal contacts being connected to the output terminal contacts by way of conductor paths which are located on the base element. Moreover, the invention relates to a base element for a filter, with at least two input terminal contacts and at least two output terminal contacts for connection of the conductors of an electrical line, the input terminal contacts being connected to the output terminal contacts via conductor paths.
2. Description of Related Art
The effect of electromagnetic interference on an electrical system can be minimized or prevented by filters, so-called EMC (electromagnetic compatibility) filters. EMC filters, which are generally lowpass filters, filter both emissions and also system emissions, i.e., they are used, on the one hand, to protect a system against the effect of external electromagnetic noise signals, on the other hand, they protect other systems or electrical devices against noise signals which are caused by the system. With EMC filters, an attempt is made to achieve poor impedance matching between the input side and output side so that maximum reflection of the noise signals arises. EMC filters are often provided on the external electrical lines of a system, for example, on the feed line. The main application of EMC filters is, for example, frequency converters.
An EMC filter must be tuned individually to the system configuration and noise signal characteristic of an electrical system so that adequate filter action is achieved. Therefore, manufacturers of EMC filters must offer a large selection of different filters in order to meet the needs of as many applications as possible. A host of filters are offered which are suitable for the most varied applications and noise signals, the filters being preconfigured components which can be directly integrated into the systems to be protected. The filters are chosen mainly based on their electrical specifications, for example working voltage and maximum allowable current.
Individual filter designs are also frequently offered for complex systems. With the objective of being able to reduce the selection of different filters and to simplify the production of an individual filter design, German Utility Model DE 203 16 051 U1 describes an EMC filter for filtering of electromagnetic interference on electric lines in which the mechanical structure is modular. The known filter has a central frame which forms the mechanical base of the EMC filter and on which the individual components can be mounted. Mounting takes place such that the individual components are mounted on the central frame in isolation from one another and are connected at least partially to one another by cabling. Preferably, a solder connection is proposed for the connection.
The configuration according to German Utility Model DE 203 16 051 U1 has the disadvantage that the components attached to the central frame must be brought into contact among one another with high wiring effort, and the configuration of the filter cannot be changed after mounting.